Place Value

Part of the Decimals, Percents & Ratios section of Coddy's Pre-Algebra journey. Lesson 1 of 53.

Many people say 0.45 is bigger than 0.5, because 45 is bigger than 5. That is wrong.

The first digit after the point counts tenths. 0.5 is 5 tenths. 0.45 is only 4 tenths and 5 hundredths. Add a zero to see it: 0.50 is more than 0.45.

$0.45 sits halfway between 0.4 and 0.5, so 0.5 is to its right$

Challenge

Put 0.3 and 0.25 on the number line. The dots move in steps of 0.05.

Start the lesson to read it in the interactive player and track your progress.

All lessons in Decimals, Percents & Ratios

1Decimals

Place ValueRounding Decimals Recap: Decimals

4Dividing Decimals

Dividing by a Decimal Dividing by 10 and 100 Dividing by a Whole Number Unit Price Recap: Dividing

7Percent Problems

Finding the Whole Discounts Tax and Tips Percent Increase Percent Decrease Recap: Percent Problems

10Proportions

Solving a Proportion Cross Products Scale Drawings Percent as a Proportion Recap: Proportions

2Adding and Subtracting

Line Up the Points Negative Decimals Making Change Recap: Add and Subtract

5Fractions and Decimals

Fraction to Decimal Decimal to Fraction Repeating Decimals Ordering Both Kinds Recap: Fractions and Decimals

8Ratios

What a Ratio Is Simplifying Ratios Equivalent Ratios Sharing in a Ratio Recap: Ratios

11Final Challenges

Final: Decimals and Percents Final: The Jacket Final: Out of a Hundred Final: The Apple Stall Final: On the Line

3Multiplying Decimals

Multiplying Decimals Times 10, 100, 1000 Bigger Products Buying by Weight Recap: Multiplying

6Percent Basics

What Percent Means Percent of a Number Percent as a Decimal What Percent Is It Recap: Percent Basics

9Rates

Unit Rates The Better Buy Speed, Distance, Time Converting Units Recap: Rates